Altirra vs Stella

Altirra is a Windows emulator for 8-bit Atari computers, covering the Atari 400/800, 1200XL, 600/800XL, 130XE, XEGS and 5200. It provides cycle-exact handling of documented hardware and models undocumented behavior, including DMA timing and undocumented 6502 instructions. Supported files include ATR, ATX, ATZ, DCM, XFD, PRO, ARC, BAS, ROM, BIN, A52, CAS and SAP. Reimplemented operating-system, BASIC and handler ROMs are included, while real Atari ROM images can be supplied for compatibility. The emulator models memory and cartridge expansions, PBI devices, modems and 65C02/65C816 accelerators. Disk options include accelerated loading, realistic timing, sounds and drive CPU emulation. Its debugger offers source stepping, breakpoints, watchpoints, history and profiling. Recording, a cheat trainer, disk browsing and text copy/paste are also included. Altirra is free under GPL version 2 for Windows 7 or later.

Stella is free, open-source software for playing Atari 2600 VCS games on a computer. It runs on Windows, macOS, and Linux under the GNU General Public License. It supports A26, BIN, and ROM images, including files in ZIP archives, as well as Supercharger games. Atari and other controllers can be emulated with a keyboard, joystick, or mouse; real Atari controllers can be used through Stelladaptor and 2600-daptor devices. Emulation features include cycle-exact TIA video and sound, stereo support, and dynamic sound resampling. Stella provides save and load for system states, automatic timeline recording, and high-score saving. Display support covers NTSC, PAL, and SECAM, with customizable CRT-style filters and bezels. A debugger offers static analysis using the Distella disassembler and runtime analysis of code, graphics, and data. The project names homebrew developers among its intended users. General requirements include SDL 2.0.14 or later and 256 MB of RAM for emulation; stable downloads include Windows binaries, a macOS disk image, an Ubuntu 22.04 DEB package, and source code for all systems.